O'Neill is preparing for his side's opening Euro 2016 qualifier against Hungary on Sunday, as the nation bids to reach its first major finals since the World Cup in 1986.
Qualification for the tournament in France in two years' time would represent Northern Ireland's debut at the European Championships.
O'Neill feels his squad has improved from their previous qualifying campaign, after a number of players last season joined up with the party as free agents.
"I don't know if we're a stronger squad than we were two years ago but I think we're a squad with more potential," he said.
"We've benefited from the time we've worked together, we've had a chance to build something, and there have been positives this summer in terms of the players' club situations.
"This time last year we still had four or five lads with no clubs sorted and it's asking a lot of someone who is unattached to come in and play qualifiers.
"But this time the ones who were looking - Craig Cathcart, Aaron Hughes, Chris Baird, Sammy Clingan, Roy Carroll - all got resolved nice and early.
"All the players have had a decent pre-season and we'll feel the benefit of that."
O'Neill also took time to praise experienced goalkeeper Carroll, who is back playing regular football at Notts County after struggling for game time in Greece with Olympiacos.
"There's no doubt about it, Roy is capable of playing at a higher level than League One but at this stage of his career the most important thing is that he is playing week in, week out," said O'Neill.
"The reports on Roy are very positive already and I went to see him myself earlier in the season when he was excellent.
"He is still an excellent goalkeeper, he's shown that with us, and now he's back enjoying himself and playing with a smile on his face.
"It's good for us that both of our other keepers, Alan Mannus and Michael McGovern, are playing regularly in the SPL but Roy is in a good frame of mind."
